CN108233155A - A kind of solid state laser cooling heat sink - Google Patents

Abstract

The invention discloses a solid-state laser cooling heat sink, which includes a cover and a heat sink base, and a columnar protrusion array is distributed on the heat sink base; an elastic heat exchange mechanism is arranged on the columnar protrusion array, and the The elastic heat exchange mechanism vibrates under the flow of the cooling medium; the cover is packaged with the heat sink base to form a cooling heat sink. The array of columnar protrusions set on the base of the heat sink effectively increases the heat exchange area inside the heat sink, and the unique porous metal fiber mesh in the elastic heat exchange mechanism inside the heat sink has the effect of strengthening heat exchange. At the same time, the wire spring coil in the elastic heat exchange mechanism increases the equivalent thermal conductivity of the cooling medium, strengthens the mixing and disturbance inside the fluid, and eliminates the fact that the heat transfer coefficient of the area behind the traditional columnar protrusion is significantly lower than that of the area on the facing surface. The disadvantage of the thermal coefficient further increases the heat transfer efficiency of the heat sink and greatly improves the cooling efficiency.

Description

A solid-state laser cooling heat sink

technical field

The invention relates to the field of optoelectronic technology, in particular to a solid laser cooling heat sink.

Background technique

In a high-power solid-state laser system, only part of the pump light absorbed by the laser gain medium is converted into laser output, and most of the rest is converted into waste heat and deposited inside the gain medium, forming a non-uniform heat distribution. Taking a solid-state laser as an example, the pump light is absorbed and attenuated exponentially when it is transmitted in the gain medium, so the heat source distribution along the length of the slab is approximately a flat "V" shape. Since the solid gain medium can only rely on the cooling of the non-pumped outer surface to take away the heat, the internal heat generation and the cooling of the outer surface will inevitably form a temperature gradient inside the gain medium, and the corresponding thermal stress and strain and the refractive index of the gain medium The change of the laser will eventually lead to the reduction of laser output power and the decline of beam quality. In the development of lasers, thermal effects have always been a major obstacle restricting the development of lasers in the direction of ultra-high power and high-quality beam quality.

In recent years, in order to meet the heat dissipation needs of high-power density electronic products, advanced and unique cooling technologies such as semiconductor refrigeration, micro-jet refrigeration, gas-liquid boiling phase cooling, and micro-heat pipe cooling have emerged and developed one after another, and are the first in microelectronics. However, there are few reports on the application of solid-state lasers, mainly because the instantaneous thermal power of solid-state lasers far exceeds that of existing high-power electronic products, and some advanced cooling technologies often appear unstable under ultra-high thermal power The deterioration of the heat transfer phenomenon brings great hidden dangers to the laser gain medium.

At present, the common cooling methods for high-power solid-state lasers are liquid direct cooling and forced convection cooling by relying on micro-channel heat sinks. Among them, micro-channel cooling heat sinks are the most commonly used and most reliable cooling methods. Micro-channel cooling technology is mainly based on micro-channel According to the research of R.A.Riddle et al.: When the flow rate is constant, the total heat transfer coefficient of the fluid in the rectangular channel is inversely proportional to the hydraulic diameter of the channel. Therefore, as the channel diameter decreases, The heat transfer coefficient increases.

At present, the equivalent diameter of high-power solid-state laser microchannel cooling heat sinks is generally between 0.1mm and 0.4mm. The increasing output power of lasers puts forward higher requirements for the cooling efficiency of microchannel heat sinks, and further reduces the cooling heat. A reduced equivalent diameter may cause blockage of the channel, and the cooling efficiency will not be significantly improved. Therefore, only reducing the hydraulic diameter of the channel cannot meet the cooling requirements of the laser. In order to improve the cooling efficiency of the micro-channel heat sink, it is necessary to set a complex channel structure inside the micro-channel to further thin the flow boundary layer or to add high thermal conductivity particles to the cooling medium flowing through the micro-channel heat sink to improve the cooling medium. Thermal conductivity, but the development cost of the complex flow channel structure is high, the processing is difficult, and it is difficult to mass-produce and manufacture, and the addition of particles with high thermal conductivity to the cooling medium will often cause blockage of the microchannel, and then make the cooling of the entire heat sink invalid. At present, the simplest parallel groove-shaped or pin-fin microchannel heat sink is widely used in high-power laser cooling schemes. The approximate "V"-shaped heat distribution inside the gain medium is matched.

Contents of the invention

The invention provides a cooling heat sink for solid-state lasers, which is used to solve the problem that the parallel groove-like or pin-rib micro-channel heat sinks with the simplest structure are widely used in the prior art high-power laser cooling schemes, and there is no better way to The problem of greatly improving the cooling efficiency of high-power lasers.

The present invention is achieved through the following technical solutions, a solid-state laser cooling heat sink, including a cover and a heat sink base,

An array of columnar protrusions is distributed on the heat sink base;

The columnar protrusion array is provided with an elastic heat exchange mechanism, and the elastic heat exchange mechanism vibrates under the action of the flow of the cooling medium;

The cover is packaged with the heat sink base to form a cooling heat sink.

Optionally, the elastic heat exchange mechanism includes a porous metal fiber mesh;

The porous metal fiber mesh runs through each columnar protrusion in the array of columnar protrusions and is fixed on the columnar protrusions.

Optionally, the elastic heat exchange mechanism further includes a plurality of wire spring coils;

Each of the wire spring coils is respectively sleeved on the porous metal fiber mesh and each of the columnar protrusions below.

Optionally, the cover is provided with an inlet and an outlet for the cooling medium to enter and exit, and after the cover is packaged with the heat sink base, an inlet liquid collection chamber and an outlet liquid collection chamber are respectively formed at the positions of the inlet and the outlet cavity.

Optionally, it also includes a flow divider arranged in the inlet liquid collection chamber; an arched channel is arranged on the flow divider.

Optionally, the arched channel of the splitter is a double-arched channel in an "M" shape.

Optionally, the columnar protrusion array is located between the inlet liquid collection chamber and the outlet liquid collection chamber.

Optionally, the height of the flow divider is consistent with the height of the columnar protrusion.

Optionally, the columnar protrusion adopts one of the following structures:

cylindrical structure;

square column structure;

and needle rib-like protrusions.

Optionally, the porous metal fiber mesh is made by braiding metal wires, and the metal wires include gold wires or copper wires.

The beneficial effects of the present invention are:

The heat exchange area inside the heat sink is effectively increased by setting the array of columnar protrusions on the base of the heat sink, and the unique porous metal fiber mesh in the elastic heat exchange mechanism inside the heat sink has the effect of strengthening heat exchange. At the same time, the wire spring coil in the elastic heat exchange mechanism increases the equivalent thermal conductivity of the cooling medium. Under the action of the flowing cooling medium, it will rotate around the columnar protrusion or jump up and down, which strengthens the mixing and disturbance inside the fluid. It eliminates the disadvantage that the heat transfer coefficient of the area behind the traditional columnar protrusion is significantly lower than the heat transfer coefficient of the facing surface area, further increases the heat transfer efficiency of the heat sink, and greatly improves the cooling efficiency.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the specific embodiments of the present invention are enumerated below.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Also throughout the drawings, the same reference numerals are used to designate the same components. In the attached picture:

Fig. 1 is a schematic structural view of a solid-state laser cooling heat sink provided by the present invention in a specific embodiment;

Fig. 2 is the front view of Fig. 1;

Figure 3 is a front view of the splitter.

In the figure: 1-cover, 11-outlet, 12-inlet, 2-outlet liquid collection chamber, 3-wire spring coil, 4-heat sink base, 5-porous metal fiber mesh, 6-inlet liquid collection chamber, 7-distributor partition, 71-double arched channel, 8-pillar protrusion.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

Please refer to Fig. 1 and Fig. 2, in the first embodiment of the present invention, a solid-state laser cooling heat sink is provided, including a cover 1 and a heat sink base 4, and a columnar protrusion array is distributed on the heat sink base 4 The array of columnar protrusions is provided with an elastic heat exchange mechanism, and the elastic heat exchange mechanism vibrates under the flow of the cooling medium, and the cover 1 and the heat sink base 4 are packaged to form a cooling heat sink.

Optionally, the elastic heat exchange mechanism includes a porous metal fiber net 5. In an optional embodiment, the porous metal fiber net 5 is made of braided metal wires, and the metal wires include gold wires or copper wires. The porous metal fiber mesh runs through each columnar protrusion 8 in the array of columnar protrusions and is fixed on the columnar protrusions 8 . Under the action of the flow of the cooling medium, the porous metal fiber mesh 5 undergoes self-vibration, which causes periodic changes in the cross-sectional area of the channel inside the heat sink, disturbs the fluid, causes the fluid to pulsate or vibrate, and destroys and thins the boundary of the fluid. Layer, to enhance the effect of heat transfer. In an optional embodiment, the columnar protrusion 8 adopts one of the following structures:

cylindrical structure;

square column structure;

and needle rib-like protrusions.

Optionally, the elastic heat exchange mechanism further includes a plurality of wire spring coils 3 , and each of the wire spring coils 3 is respectively sleeved on each of the columnar protrusions 8 on and below the porous metal fiber mesh 5 . The wire spring coil 3 on the columnar protrusion 8 increases the equivalent thermal conductivity of the cooling medium. Under the action of the flowing cooling medium, the wire spring coil 3 will rotate around the columnar protrusion 8 or jump up and down, which strengthens the fluid internal The mixing and disturbance of the traditional columnar protrusion 8 eliminates the disadvantage that the heat transfer coefficient of the area behind the traditional columnar protrusion 8 is significantly lower than the heat transfer coefficient of the facing surface area, and further increases the heat transfer efficiency of the heat sink.

Optionally, the cover 1 is provided with an inlet 12 and an outlet 11 for the cooling medium to enter and exit, and the cover 1 and the heat sink base 4 are packaged to form inlets at the positions of the inlet 12 and the outlet 11 respectively. Liquid collection chamber 6 and outlet liquid collection chamber 2. The columnar protrusion array is located between the inlet liquid collection chamber 6 and the outlet liquid collection chamber 2 .

Optionally, referring to FIG. 3 , the cooling heat sink further includes a flow divider 7 arranged in the inlet liquid collection chamber 6 , and an arched channel is arranged on the flow divider 7 . The height of the flow divider 7 is consistent with the height of the columnar protrusion 8 . In an optional embodiment, the arched channel of the splitter 7 is a double arched channel 71 in an "M" shape that matches the heat distribution of the laser gain medium.

Please refer to FIGS. 1-3. In the second embodiment of the present invention, a microstructure high-power solid-state laser cooling heat sink with small flow resistance and high convective heat transfer coefficient is provided, including a cover 1 and a heat sink base 4, The heat sink base 4 is distributed with an array of columnar protrusions. In a preferred embodiment of the present invention, each columnar protrusion in the array of columnar protrusions can be distributed in a staggered manner, or arranged in order in rows and columns. Here, the present invention The embodiment does not make a unique limitation on the distribution manner of the columnar protrusion array. An elastic heat exchange mechanism is arranged on the columnar projection array, and the elastic heat exchange mechanism vibrates under the action of the flow of the cooling medium. The columnar protrusion array and the elastic heat exchange mechanism form a microstructure with enhanced heat exchange effect. After the cover 1 is packaged with the heat sink base 4 with enhanced heat exchange microstructure, a cooling heat sink is formed. The lower surface of the entire cooling heat sink and the laser The gain medium is closely connected to cool the laser gain medium.

The cover 1 is provided with an inlet 12 and an outlet 11 for the cooling medium to come in and out, and the inlet 12 and the outlet 11 are all set as circular through holes with the same diameter. After the cover 1 and the heat sink base 4 are packaged, respectively The positions of the inlet 12 and the outlet 11 form the inlet collecting chamber 6 and the outlet collecting chamber 2 . A flow divider 7 is arranged in the inlet liquid collection chamber 6 , and an arched channel is arranged on the flow divider 7 . The height of the splitter baffle 7 is consistent with the height of the columnar protrusion 8 , and the lower surface of the splitter baffle 7 is attached to the upper surface of the heat sink base 4 , and a stable connection is achieved through a welding process.

In this embodiment, the columnar protrusion array is located between the inlet liquid collection chamber 6 and the outlet liquid collection chamber 2. The columnar protrusions 8 adopt a cylindrical structure with a diameter of 0.5 mm to 1 mm and a height of 2 mm to 4 mm. The size of the columnar protrusion 8 and the equivalent diameter of the internal flow channel are both larger than the equivalent diameter of the traditional microchannel, which can effectively reduce the flow resistance of the heat sink.

The elastic heat exchange mechanism includes a porous metal fiber net 5. Preferably, the porous metal fiber net 5 has a three-dimensional network structure, the thickness of the porous metal fiber net 5 is 0.05-0.1 mm, the porosity is 0.6-0.8, and the diameter is 0.02 mm. ~0.05mm metal wire braided, the metal wire includes strong toughness, high thermal conductivity, corrosion-resistant gold wire or copper wire, or other toughness, high thermal conductivity, corrosion-resistant metal wire. The porous metal fiber mesh 5 runs through each columnar protrusion 8 in the array of columnar protrusions and is fixed at the middle position on the columnar protrusion 8 by vacuum diffusion welding. Under the action of the flow of the cooling medium, the porous metal fiber mesh 5 undergoes self-vibration, which causes periodic changes in the cross-sectional area of the channel inside the heat sink, disturbs the fluid, causes the fluid to pulsate or vibrate, and destroys and thins the boundary of the fluid. Layer, to enhance the effect of heat transfer.

The elastic heat exchange mechanism also includes a plurality of wire spring coils 3 , and each wire spring coil 3 is sleeved on each columnar protrusion 8 on and below the porous metal fiber net 5 . The wire diameter of the wire spring coil 3 is 0.05-0.1 mm, the coil height is 0.5-1 mm, the coil diameter matches the equivalent diameter of the columnar protrusion 8, and the wire spring coil 3 only wraps around the columnar protrusion inside the cooling heat sink 8 rotation or jumping up and down, no horizontal displacement. The wire spring coil 3 on the columnar protrusion 8 increases the equivalent thermal conductivity of the cooling medium. Under the action of the flowing cooling medium, the wire spring coil 3 will rotate around the columnar protrusion 8 or jump up and down freely, which strengthens the flow of the fluid. The internal mixing and turbulence eliminates the disadvantage that the heat transfer coefficient of the area behind the traditional columnar protrusion 8 is obviously lower than that of the area facing the flow surface, and further increases the heat transfer efficiency of the cooling heat sink.

Due to the approximately "V"-shaped heat distribution inside the laser gain medium, the arched channel of the splitter 7 is a double arch in an "M" shape that matches the approximately "V"-shaped heat distribution inside the laser gain medium Shaped channel 71. The height of the highest point of the double-arch channel from the upper surface of the diversion partition is 0.5-1mm, and the height of the lowest point from the lower surface of the diversion partition is 0.5-1mm.

The cooling medium enters the inlet liquid collection chamber 6 of the cooling heat sink from the inlet 12 of the cover 1, and under the action of the splitter 7 with double arched channels, the cooling medium flows through different areas in the columnar protrusion array inside the cooling heat sink. Cooling medium flow to match the heat distribution in the laser gain medium. When the cooling medium flows inside the cooling heat sink, the ultra-thin porous metal fiber mesh 5 sintered in the middle of the columnar protrusion 8 fluctuates periodically up and down under the action of the cooling medium flow, and then drives the The wire spring coil 3 jumps up and down, and at the same time, the wire spring coil 3 also rotates around the columnar protrusion 8 under the impact of the cooling medium (or cooling liquid), which strengthens the mixing and disturbance inside the fluid and effectively thins the The fluid boundary layer in the wall-adhering area strengthens the convective heat transfer at the rear edge of the columnar protrusion 8, thereby improving the cooling efficiency of the entire cooling heat sink.

Apparently, the present invention effectively increases the heat exchange area inside the heat sink by arranging the array of columnar protrusions on the base of the heat sink. The unique porous metal fiber mesh in the elastic heat exchange mechanism inside the heat sink will Natural vibration occurs, which causes periodic changes in the cross-sectional area of the internal channel of the heat sink, turbulence to the fluid, causes the fluid to pulsate or vibrate, destroys and thins the boundary layer of the fluid, and has the effect of enhancing heat transfer. At the same time, the wire spring coil in the elastic heat exchange mechanism increases the equivalent thermal conductivity of the cooling medium, and under the action of the flowing cooling medium, it will rotate around the columnar protrusion or jump up and down, which strengthens the mixing and disturbance inside the fluid , Eliminate the disadvantage that the heat transfer coefficient of the area behind the traditional columnar protrusion is significantly lower than the heat transfer coefficient of the facing surface area, further increase the heat transfer efficiency of the heat sink, and greatly improve the cooling efficiency.

In a word, the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A solid-state laser cooling heat sink, comprising a cover and a heat sink base, is characterized in that, An array of columnar protrusions is distributed on the heat sink base; The columnar protrusion array is provided with an elastic heat exchange mechanism, and the elastic heat exchange mechanism vibrates under the action of the flow of the cooling medium; The cover is packaged with the heat sink base to form a cooling heat sink. 2. solid-state laser cooling heat sink as claimed in claim 1, is characterized in that, The elastic heat exchange mechanism includes a porous metal fiber mesh; The porous metal fiber mesh runs through each columnar protrusion in the array of columnar protrusions and is fixed on the columnar protrusions. 3. The solid-state laser cooling heat sink according to claim 2, wherein the elastic heat exchange mechanism also includes a plurality of wire spring coils; Each of the wire spring coils is respectively sleeved on the porous metal fiber mesh and each of the columnar protrusions below. 4. The solid-state laser cooling heat sink according to claim 1, wherein the cover is provided with an inlet and an outlet for the cooling medium to enter and exit, and the cover and the heat sink base are packaged respectively in the The positions of the inlet and outlet described above form an inlet manifold and an outlet manifold. 5 . The solid-state laser cooling heat sink according to claim 4 , further comprising a divider baffle arranged in the inlet liquid collection cavity; an arched channel is arranged on the divider baffle. 6 . 6 . The solid-state laser cooling heat sink according to claim 5 , wherein the arched channel of the splitter partition is a double arched channel in an "M" shape. 7 . The heat sink for cooling solid-state lasers according to claim 4 , wherein the columnar protrusion array is located between the inlet liquid collection chamber and the outlet liquid collection chamber. 8 . 8 . The solid-state laser cooling heat sink according to claim 5 , wherein the height of the shunt partition plate is consistent with the height of the columnar protrusion. 9 . 9. The solid-state laser cooling heat sink according to claim 2, wherein the columnar protrusion adopts one of the following structures: cylindrical structure; square column structure; and needle rib-like protrusions. 10. The heat sink for cooling solid-state lasers according to claim 2, wherein the porous metal fiber mesh is made by weaving metal wires, and the metal wires include gold wires or copper wires.